Originally Posted by
MAH4546
It used to be a 763 in the 1990s.
It's probably not an issue of demand - you can fill a 777 between Miami and Seattle (or Boston and Seattle or New York and Seattle and so on) if you really want to - but these days it's more about frequency (there are up to 6 daily Miami-Seattle flights between AA, AS, DL and NK) and tight capacity on domestic routes.
And MIA-LAX has it's widebody back.
The 763 was the first leg of the MIA-SEA-NRT (change of gauge in SEA). AA was carrying a number of passengers from S.America to MIA to SEA to NRT at the time. (The 763s had absolutely nothing to do with their relationship with AS)
At this point, the 738 is a far less costly plane to fly on that route. And, at peak times, AA has added a 2nd daily flight on the 319. The narrowbodies give a ton more flexibility of having more than one flight per day.